WASHINGTON -- Four pro-industry members of the Nuclear Regulatory Commission, along with Rep. Darrell Issa (R-Calif.), launched a public assault on the panel's chairman Friday, accusing him of mismanagement and heavy-handedness. Although the fight is framed by the commission members as personal, it is at root political and ideological, a dueling report put out Friday night by Rep. Ed Markey (D-Mass.) shows.

Commission Chairman Gregory Jaczko is a longtime proponent of reforming safety standards at nuclear power plants and was the first chair to win the seat without the support of the industry. The other four members were all strongly backed by the nuclear industry when they were nominated and confirmed.

In early December, the four other commission members wrote a letter to White House Chief of Staff William Daley accusing Jaczko of "increasingly problematic and erratic" behavior.

The letter was made public by Issa, chairman of the House Oversight and Government Reform Committee. All five commission members are scheduled to appear Wednesday before his panel. Issa has requested that a White House representative attend as well.

Jaczko is a former staffer to Senate Majority Leader Harry Reid (D-Nev.), who successfully fought off the industry's effort to use Yucca Mountain in his state as a dumping ground for nuclear waste. Jaczko also worked for Markey, an outspoken proponent of legislation to address climate change and a critic of the industry's safety record.

The push for nuclear safety reforms was galvanized by the nightmare scenario in Japan, where radioactivity still haunts large swaths of the area around the Fukushima nuclear plant that failed in March 2011.

"The actions of these four Commissioners since the Fukushima nuclear disaster has caused a regulatory meltdown that has left America's nuclear fleet and the general public at risk," said Markey in a statement. "Instead of doing what they have been sworn to do, these four Commissioners have attempted a coup on the Chairman and have abdicated their responsibility to the American public to assure the safety of America's nuclear industry. I call on these four Commissioners to stop the obstruction, do their jobs and quickly move to fully implement the lessons learned from the Fukushima disaster."

In his own letter to Daley, Jaczko responded to the allegations, Reuters reported. "Unfortunately, all too often, a majority of this current commission has taken an approach that is not as protective of public health and safety as I believe is necessary," he wrote.

Update: 5:29 p.m. -- Sen. Barbara Boxer (D-Calif.), who chairs the Senate Environment and Public Works Committee, came to Jaczko's defense on Saturday. In a statement, she said, "Instead of applauding the Chairman of the Nuclear Regulatory Commission for his swift and effective response to Fukushima, his fellow commissioners are attacking him. We must move away from the 'do nothing' culture of the NRC and support Chairman Jaczko as he translates the lessons of Fukushima into an action plan that will make America's nuclear plants the safest in the world."

Next Thursday, all five commissioners are set to testify before Boxer's committee on the NRC recommendations in the aftermath of Japan's nuclear disaster.

Update: 8:49 p.m. -- Early on Saturday morning, lobbyists for major utilities began reaching out to Democrats on key committees, asking them not to jump quickly to Jaczko's defense, according to people privy to the lobbying push. One senior congressional aide said the speed and timing of the effort suggested a coordinated action against the chairman.

"It's obvious these guys are all in on this coup. They've been whining about Jaczko, particularly after Japan and what he's been doing since then, consistently," said the aide.